A number of carburation devices are known which provide various teachings for improving the fuel efficiency of internal combustion gasoline engines. Conventional carburation devices produce a combustible fuel and air mixture by causing air to be drawn through a venturi into which liquid gasoline is fed. However, the fuel and air mixture, which includes an air stream containing a mist of small liquid gasoline droplets and gasoline vapor resulting from evaporation of the droplets, is not an ideal mixture. It has long been known that the efficiency of the engine is partially dependent upon the degree to which the liquid gasoline is vaporized. The lack of complete vaporization by conventional carburetors leads to disadvantages, such as carbon build-up in the engine due to too rich of an air-fuel mixture being burned in certain engine cylinders and too lean of a fuel-air proportion at other points resulting from inertia of unvaporized droplets of liquid gasoline that in turn causes centrifugal separation of some of the liquid droplets from the air and vapor flow at bends within the intake manifold. Hot air injection into the intake manifold to improve vaporization, and thereby improve combustion and hence fuel efficiency, and also to reduce pollutants has been utilized, but this involves a decrease in the thermodynamic efficiency of the engine. U.S. Pat. Nos. 3,943,900, 4,137,875, and 4,167,166 disclose mixing chambers positioned between a conventional carburetor and the engine's intake manifold to mix additional air with the fuel-air mixture produced by the carburetor to accomplish increased vaporization. U.S. Pat. Nos. 4,062,334, 2,446,034, 2,351,250, and 2,075,330 disclose multiple, sequential carburation systems to improve vaporization of the liquid gasoline. U.S. Pat. No. 4,175,525 discloses a chamber which vaporizes liquid gasoline by bubbling air through gasoline, producing a gasoline vapor in a container, drawing the gasoline vapor into the region between the throttle plate and the intake manifold, and providing a check valve to prevent explosions due to backfiring. The device disclosed draws only several ounces of liquid gasoline from each gallon of gasoline consumed by the carburetor, vaporizes it by bubbling air through the several ounce quantity, and injects fully vaporized gasoline downstream from the main carburetor. This is alleged to allow the main carburetor to be adjusted to produce a leaner mixture. However, the air-fuel mixture produced by the venturi action of the carburetor nevertheless includes a substantial amount of unvaporized liquid gasoline in the form of droplets which cause the above-mentioned problems.
Thus, there remains an unmet need for an improved carburation system which greatly reduces the amount of unvaporized gasoline in the form of a gasoline mist entering the intake manifold of an engine.